Screw-cutting die



2Y sheets-sheet 1.

(No Model.)

J HARTNESS soRBW CUTTING DIE. No. 529,169.

Patented Nov. 13, 1894.'

MTN 55555:

(No Mdel.) v sheetssheet 2. "1'. HARTNESS. SCREW UUTTING DIE.

N0. 529,169. l Patented Nov. 13,1894.

UNITED STATE-sv 'PATENT OFFiCE.

JAMES HARTN ESS, OF SPRIGFIELD, VERMONT.

SCREW-CUTTING DIE.

PEGIFICATION forming part of Letters Patent No. 529,169, dated November 13, 1894.

Application 1iilel January 9, 1894. Serial No. 496,260. (No model.)

To all whom' it may con/cern:

Be it known that I, JAMES HARTNEss, of Springfield, in the county of Windsor and State of Vermont,have invented certain new and useful Improvements in Screw-Cutting Dies, of which the following is a specification.

This invention relates to certain improvements in screw-cutting dies, and the main object in view is to obtain greater accuracy in screw-cutting than is possible with the dies heretofore devised. Y

The greatest essential to accuracy in screwcntting is a perfect alignment of the axis of the die and the work, and hitherto it has been found practically impossible to maintain such an alignment. It is well known that,if a die is started on its work at or nearly at the correct angle, it will follow the work, if freevto do so, and will assume a position with its axis in alignment with the axis thereof. I therefore contemplate the construction of a die without a fixed axis, but capable of assuming the position which the work demands, at the same time providing for rigidity of the die with regard to the direction of the cutting strain, and herein my invention may be said to chiefly reside. v

The invention has also in View certain improvements relative to the construction of opening dies. Y

The accompanying drawings illustrate a construction which embodies the invention.

Figure 1 shows a front elevation of the die, represented as broken out at one place, with parts in section thereat. Fig. l represents a perspectiveviewofoneof thedie-cutters. Fig. 2 shows a longitudinal section on line 2-2 of Fig. 1. Fig. 3 shows a cross-section on line 3-3 of Fig. 2. Fig. 4 shows a section on line 4.--4 of Fig. 3. Fig. 5 shows a cross-section on line 5-5 of Fig. 4. Fig. 6 shows a crosssection on line66 of Fig. 2. Fig. 7 shows a side elevation of the die. Fig. 8 shows a top plan view of the die, represented as broken out at one place, with parts in section thereat.

The same letters of reference indicate the same parts in all the figures In the drawings: the letter a designates a cylindrical support or holder, designed to be stationarily mountedxon the turret or other .carriage of a lathe, or applied to a suitable part of a bolt-cutter, drill-press or other machine. Said holder is preferably formed with an annular flange a. at its forward end, in which flange is a p heripheral groove a2, and a radially-extending slot or slide-way a3 (Figs. 2fand 8), the office whereof will appear herein.- a ter.

e e', represent the thread-cutters or chasers, which are carried by a die-body, here shown as composed of two members b c, one of which, b, is in the form of a cylinder and occupies the bore of the holder a, and in accordance with this invention is capable of universal lateral play in said holder to a limited extent, said member b being loosely fitted to the holder with clearance all around, as shown in the drawings. The member Z2 is engaged with the holder a. by means of studs b2, fastened in the holder and projecting into pockets b formed in the member b, said pockets being of suitable size to permit the desired univer- Isal play of the member.

When the die is used in a horizontalfposition, the weight of the body is connterbalanced by means of cushions, in the form of helicalsprings b3 (Fig. 5), contained in pockets b4 formed in the member b and bearing against screws b5 fastened in the holder. When the die is disposed vertically, these springs will not be found necessary. The other member,

c, of the die-body is of annular form, and bears against the front end of the. holder a, and has a flange c (Figs. 2 and 4), which enters the bore of the holder and bears against the front end of the memberb, the same clearance being allowed around the said flange as around the member b and for the same purpose. The two members are rotatively connected by means of lugs c2 (see Fig. 2 and dotted lines inkFig. 4) on the member b, and notches asin the flange c engaged by said lugs, this construction permitting longitudinal movement of the member c with respect to the kmember b, but no rotative movement of the one Without the other.

When the die is horizontally disposed, the member c is yieldingly held against the member b andholdero. by springs c4 (Fig. 4), which surround screws c5 fastened in the holder, said screws extending through openingsc6 in the member c and into pocketsc7 in the latter, the springs bearing against the base of the pockets and the heads of the screws.

It is to be noted that the openings cG are of a size giving elearence all around the screws.

The springs c4, like the springs b, will not be necessary when the die is disposed vertically. Said springs should be stift enough to only overcome the gravity ofthe die-body and hold the same against the perpendicular face of the holder. The joint occurring where the two body-members b c abut is effectually closed to exclude dirt and chips, by a ilat resilient band d (Figs. 2 and 4), sprung into a recess in the wall of the central opening of the body.

The member c is provided in its face with divergin g slots e (Figs. 1 and 3), which receive the thread-cutters or chasers e', and with segmental concavities e2 (Fig. 1) adjacent to the slots to permit the escape of the chips from the die. The cutters e are provided with transverse grooves e5 (Figs. 1 and 1), which receive the acting portions f5 of a cam f, the latter being fitted to turn on a seat formed for it on the die-body. Rotativo movement of the cam in opposite directions moves the cutters c from operative to inoperative adjustment and vice versa, or,in other words, opens and closes the die. The cam is embraced by a sleeve or cam-holderf, which is fitted to rotate on the member c of the die-body, said camholder having a shoulder j projecting over the front of the cam. Said cam-holder and cam are adjustably connected by means of a screw f2 (Figs. 1 and 2), engaged with a screw-threaded bore in the cam-holder and having a head f3 engaging a groove f7 in the cam, so that upon turning said screw the cam may be adjusted in the cam-holder and the cutters correspondingly adjusted.

To automatically open the die, I provide a ring or collar g, which is fitted to turn in an annular recess between the cam-holderf and the body-member c, a portion of said collar projecting outside of the cam-holder, and being knurled at this part to facilitate manipulation of the collar. The desired clearance is allowed between the collar and the holder o., and the joint between said collar and the holder a is closed bya packing-ring h, occupying a groove a2 in the holder a., and pressing outward against the collar. The latter is formed in that portion which fits between the cam-holder and the die-body, with obliquely-extending slots h2, which embrace pins h3 fastened in the sleeve f' and thereby hold the latter on the body.

A spiral spring e' is contained in a curved cavity in the rear side of the body-member c, and bears at one end against a pin c" fastened in the latter, and at the opposite end against a pin i2 fastened in the collar g, so that said spring exerts a constant pressure in a direction to advance the oblique slots of the collar upon the pins in the cam-holder, thereby locking the collar and the cam-holder tightly together and also rotating the cam to open the die.

The die is closed by rotating the cam-holder against the tension of the spring e, and for this purpose the cam-holder f is equipped with a handle j, by which it may be partly rotated. Said handle serves also to move a deteut j (Fig. 3), which is adapted to hold the die closed, said deteut being pivoted at j (Fig. 3) to the holder f', and having a lugj2 for engagement with a notch in the body, the handle being formed on the deteut.

Means are provided through the medium of which longitudinal movement of the member c effects the disengagement ofthe deten t, said means including a pin, comprising a spherical end m (Figs. l and 8) engaging the radial slot a3 in the holder, a neck m extending through the narrow front of the said seat and into a bore m2 in the member c, an enlarged cylindrical central part m3 loosely fitting said bore, a neck m4, and a conical head m5 beyond the latter.

A short tappet-rod n (Figs. 2 and 3) has a sliding engagement with the body-member c, and one end normally bears against the neck m4 when the die is closed, while the other end bears against the detentj. It will be seen that au outward longitudinal movement of the body-member c will cause the rod n to ride on the conical head m5 and be thrust outward thereby and caused to disen gage the detent from the die-body.

It is to be noted that all parts making up the die proper are closely tted together, while there is no part of the die proper which closely fits the holder. This gives the die properalatitudc of independentadjustment, permitting it to adjust itself to the work and assume au axial adjustment with regard thereto irrespective of theholders axis. By this arrangement, I am enabled to obtain a more nearly perfect alignment of the axis of the work and the die than has hitherto been possible.

It will be observed that the die `is at all times rigidly held against the cutting strain by the engagement of the die-body with the holder'through the studs b2 and pockets b (Fig. 4).

In the operation of the die, it is crowded on to the work with the cutters closed, the work being rotated and the holder fed forward along the work as usual in machines of this class. When the forward movement ofthe holder ceases, the member c of the die-body and the cutters thereon continue to be moved forward by the continued rotation of the work until the deteut j is disengaged, in the inauner previously described, whereupon the spring 1I forces the cutters outwardly through the described intermediate means, and the operation ceases.

The connection between the cam f and the cam-holder f afforded by the screw f2 enables the cam to be turned independently of the holder for a more or less fine or minute adjustment of the cutters, and also enables the holder and cam to be moved together for a quick adjustment.

' lt is evident that the invention may be embodied in other forms than here shown, and is not therefore limited in this respect.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-

l. A screw-cutting die comprising a support or holder, a cutter-carrying body held thereby, and connections between the support and body with provisions rendering the latter capable of lateral movement bodily in the support to adjust itself axially with respect to the work without necessarily changing the angular relation of its axis and that of the work. i

2. A screw-cutting die comprising a support or holder, a cutter-carrying body held thereby, connections between the support and body with provisions rendering the latter capable of lateral movement bodily in the support to-adj ust itself axially with respect to the work without necessarily changing the angular relation of its axis and that of the work, and means for yieldingly supporting the said body.

3. A screw-cutting die comprising a support or holder, a cutter-carrying body held thereby, and connections between the support and body with provisions rendering the latter capable of lateral movement bodily in thesupport to adj ust itself axially with respect to the work without necessarily changing the angular relation of its axis and that of the work, while rigidly holding the die against rotary cutting strains.

4. An automatically-opening die, comprising a holder, a body therein, connections between the holder and body with provisions wherebythe latter is yieldingly held against lateral strains, rigidly held against rotary cutting strains, and rendered capable of a longitudinal movement; adjustable cutters normally held in their open adjustment in said bady; means for holding said cutters in their closed adjustment; and means operated by a longitudinal movement of the body for releasing the cutters and allowing them to assume their normal adjustment.

5. An automatically-opening die, comprising a holder or support, a die-body therein, connections between the holder and die-body with provisions whereby the latter is yieldingly held against lateral strains and rigidly held against rotary strains, and rendered capable of longitudinal movement, radiallymovable cutters, automatic means for moving said cutters to their open adjustment, and locking-mechanism that holds the cutters in their closed adjustment and is released by a relative longitudinal motion of the die-body to its holder. Y

6. An openingdiegcomprising a holder, a die-body, connections between the holder and die-body with provisions for permitting a slight lateral motion of the latter, cam-operated cutters or chasers fitting in radial slots in theface of said body, and means for re- 8. An opening die comprising a holder, a

spring-supported die-body, and means of connection between the holder and die-body with provision for rigidly resisting cutting strains and for bodily movement of the die-body to adjust itself to the work without changing the relative angularity of the axes of the diebody and work.

9. An adjustable screw-cutting die, with provisions to permit its taking the axial position of the work, without affecting the angular relation of its axis and that of the work, and provided with means for resisting the cutting strains.

l0. A n opening-die, provided with cam operated cutters or chasers fitting in radial slots in the face of the die-body, a cam-holder engaged with said cam, and a spring-pressed locking-collar having means for engagement with said cam-holder.

1l. An automatically-opening screw-cutting die, comprising in its construction a support or holder, a cutter-carrying body, connections between the holder and body with provisions rendering thelatter capable of limited lateral play and also capablel of independent longitudinal movement, Whil rigidity in the direction of the cutting strain is maintained, means for yieldingly resisting ICO longitudinal movement of said body, and

means controlled by the independent longitudinal adjustment of the body for simultaneously retracting or opening the cutters.

l2. An automatically-opening die, comprising a holder, a die-body, cutters carried thereby, a rotative cam for opening and closing the cutters, a cam-holder engaged with the cam, a collar rotatable on the die-body and adapted to engage the cam holder, a

spring actuating the said collar and therev through tending to movegthe cam and its holder to open the die, and a detent for holding the cam in position tovclose the die.

13. An automatically-opening die, comprising in its cqnstruction a holder, a die-body supported therein, connections between the holder and body with provisions rendering the latter capable of independent longitudinal movement, radial 4cutters supported by said body, a rotativecam controlling said cutters, a spring tending to throw the cam to position to open the die, a detent for holding the cam against said spring, a pin engaged with the holder and -held thereby from longitudinal movement and having a sliding engagement with the body, said pin having a tapered part, and a tappet-rod adapted to ride on said tapered part under longitudinal movement of the body and disengage the detent.

14. A screw-cutting die, comprising a diebody having radial slots, cutters or chasers movable in said slots, a rotatable cam adapted to move the cutters to their open and closed adjustments, a cam-holder rotatable on the die-body, and an adjustable connection between said holder and cam whereby the latter may be minutely adjusted, the holder being adapted to be moved with the cam to effect a quick adjustment.

15. A screw-cutting die, comprising a diebody having radial slots, cutters or chasers movable in said slots, a rotatable cam adapted to move the cutters to their open and closed adjustments, a cam-l1older rotatable on the die-body, an adjusting-screw engaged as de scribed with the cam-l1older and cam whereby the latter may be independently rotated, said screw constituting a connection between the holder and cam so that the two may be rotated together to eect a quick adjustment.

16. A screw-cutting die, comprising a diebody having radial slots, cutters or chasers movable in said slots, a rotatable cam adapted to move the cutters to their open and closed adjustments, a cam-holder rotatable on the die-body, an adjustable connection between said holder and cam whereby the latter may be minutely adjusted, the holder and cam being movable togetherto eect a quick adjustment of the cam,and a spring-pressed collar adapted to partially rotate said cam-holder.

17. A screw-cutting die, comprising adiebody having radial slots, cutters or chasers movable in said slots, a rotatable cam adapted to move the cutters to their open and closed adjustments, a cam-holder rotatable on the die-body, an adjustable connection between said holder and cam whereby the latter may be minutely adjusted, the holder and cam being movable together to eect a quick adj ustment of the cam, a spring pressed collar adapted to partially rotate said cam-holder, a detent adapted to hold the cam-holder against the action of said collar, and means operated by a longitudinal movement of the die-body for displacing said detent.

18. A screw-cutting die comprisinga holder, atwo-part die-body, connections between one member thereof and the holder, connections between the two members of said body with provisions forindependentlongitudinal movementof one without disconnection of the two members, radially-movable cutters or chasers in the longitudinally-movable member, means for automatically moving said cutters outwardly to their open adjustment, a detent.l

adapted to hold the cutters in their closed adj ustment, and detent-displacing devices operated by a longitudinal movement of the cutter-carrying member.

19. A screw-cutting die comprising a holder, a two-part die-body, connections between one member thereof and the holder, connections between the two members of said body with provisionsforindependentlongitudinal movement of one without disconnection of the two members, radiallyfmovable cutters or chasers in the longitudinally-movable member, anda spring-pressed collar engaged with the camholder and adapted to turn the same in one direction.

In testimony whereof I have signed my name to this specification, in the presence of two subscribing witnesses, this 22d day of December, A. D. 1893.

JAMES HARTNESS.

Witnesses:

G. O. GRIDLEY, W. D. WooDsoN. 

